I completely CLA'd my 4x5 Speed Graphic.. It was nerve-racking at some points (governer mechanism and winding the shutter blinds back mostly) but honestly it isn't that bad at all..
Jon, what material did you use for the curtain? I am curious! I'd love a new/spare curtain!

Hi - Well, gather 'round... it's an interesting yarn. At the time I started, the only known source for shutter curtain material in the universe was Micro-Tools. However, at the time there were a number of threads making the rounds that impugned the quality of the Micro-Tools material, to say the least. Stories of curtains that stuck to themselves and/or leaked light kept me from taking the plunge. So, I looked for an alternate source forever with no luck. Finally, after probably ten or more hours of research, I blundered across prefabricated Leica curtains from a Japanese seller on eBay. I had the brilliant idea to ask him if he bought the fabric from Micro-
Tools. The answer was "no, it is Japanese fabric." He said it was much better than Micro-Tool's, and he offered to sell some to me. It was twice the price but remember, I was gun-shy, so I went for it.

Well, in the meantime, curiosity got the better of me and I asked the Grand Master of Graflex repair if he would send to me a swatch of the M-T material. Turns out the Japanese material really is different from the M-T stuff. The Japanese is about 50% heavier per unit area. When held right up against a strong halogen point-source, the Japanese material shows zero transmittance versus the M-T material which shows occasional micro-pinholing. (I have no reason to believe the pinholes are of concern in practical use, by the way. The Grand Master has rebuilt more shutters in the last year than I have in my five previous lives, and he has never had any problem with the M-T material.)

If you are really interested, then I could send to you a swatch of each, as long as you promised to return it. I ended up using the Japanese material despite my concerns that the extra weight would throw off the timing of the shutter. As it turns out, I had no such problem. The best part of all was unanticipated. Since the entire camera was apart, I had a chance to lube everything properly. The combination of the pliable new curtain material and the lube job yielded astounding smoothness in the action. I think we all have become accustomed to really noisy, graunchy Graflex shutters. I no longer believe that such nastiness is par for the course with monster SLR's; I think it is a symptom of a camera that is crying hoarsely to be rebuilt.

Now bear in mind that these are just the ravings of a novice camera hack. I would recommend spending plenty of time hanging around the Graflex.org site if you really want to learn something. The collective wisdom of the Masters will have you on your way to SLR heaven in no time. Best of luck.